3-halo-1,2,8,9-tetraazaphenalenes

ABSTRACT

3-HALO-1,2,8,9-TETRAAZAPHENALENES OPTIONALLY SUBSTITUTED IN THE 4, 5, 6, 7 AND/OR 9 POSITIONS AND THEIR SALTS ARE INTERMEDIATES FOR THE PREPARATION OF THE CORRESPONDING 3-AMINO-1,2,8,9-TETRAAZAPHENALENES WHICH ARE CARDIOVASCULAR AGENTS. REPRESENTATIVE EMBODIMENTS ARE 3-CHLORO1,2,8,9-TETRAAZAPHENALENE AND 3-BROMO-9-METHYL-1,2,8,9TETRAAZAPHENALENE.

United States Patent 3,560,500 3-HALO-1,2,8,9-TETRAAZAPHENALENES Karl J. Doebel, Ossining, and John E. Francis, Pleasantville, N.Y., assignors to Geigy Chemical Corporation, Ardsley, N.Y.

No Drawing. Continuation-impart of application Ser. No. 718,227, Apr. 2, 1968, which is a continuation-in-part of applications Ser. No. 445,762, Apr. 5, 1965, Ser. No. 539,303, Apr. 1, 1966, and Ser. No. 583,980, Oct. 3, 1966. This application Mar. 24, 1969, Ser. No.

Int. Cl. C07d 51/04 US. Cl. 260250 7 Claims ABSTRACT OF THE DISCLOSURE 3-halo-l,2,8,9-tetraazaphenalenes optionally substituted in the 4, 5, 6, 7 and/or 9 positions and their salts are intermediates for the preparation of the corresponding 3-amino-l,2,8,9-tetraazaphenalenes which are cardiovascular agents. Representative embodiments are 3-chloro- 1,2,8,9-tetraazaphenalene and 3-bromo-9-methyl-1,2,8,9- tetraazaphenalene.

CROSS REFERENCE This is a continuation-in-part of copendingapplication Ser. No. 718,227 filed Apr. 2, 1968 which in turn is a combination-in-part of applications, Ser. Nos. 583,980, 539,303 and 445,762 filed Oct. 3, 1966, Apr. 1, 1966 and Apr. 5, 1965 respectively, all now abandoned, Ser. No. 539,303 being a continuation-in-part of Ser. No. 445,762 and Ser. No. 583,980 being a continuation-in-part of Ser. Nos. 539,303 and 445,762.

DETAILED DESCRIPTION The present invention pertains to 3-halo-1,2,8,9-tetraazaphenalenes of the formula:

wherein R is hydrogen, (lower)alkyl, phenyl or phenyl(lower) alkyl;

R is hydrogen or phenyl;

R is hydrogen, chloro, bromo, hydroxy, (lower)alkoxy,

carboxy or nitro; and

Y is chlor or bromo and to the acid addition salts thereof.

The term alkyl and derivations thereof such as alkoxy denotes a straight or branched hydrocarbon chain. When qualified by the designation (lower), such chain 'will contain up to and including 6 carbon atoms. Illustrative of such alkyl groups are methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, t-butyl, pentyl, hexyl, and the like, While illustrative of such alkoxy groups are methoxy, ethoxy, propoxy, butoxy and the like.

The compounds of the present invention are identified herein as derivatives of the novel parent tricyclic nucleus Patented Feb. 2, 1971 The tetraazaphenalenes of the present invention are valuable chemical intermediates for the preparation of the corresponding 1,2,8,9-tetraazaphenalenes bearing an amino function in the 3-position and described in Serial No. 718,227. This amino group may be a simple .alkyl, phenyl, benzyl or chlorophenyl substituted amine. Alternatively the amino function can be comprised in a nitrogen-containing heterocyclic group. Such a heterocyclic group can be a 5 to 7 membered monocyclic system optionally containingan oxygen atom or an additional nitrogen atom as a ring member with the remainder of the ring members being carbon atoms. A benzene ring can be fused to such heterocyclic rings thus including 10 membered bicyclic systems. Typical of such heterocyclic groups are pyrrolidino, piperidino, hexamethyleneimino, morpholino, piperazino, N'-alkylpiperazino, dialkylmorpholino, tetrahydropyridino and the like.

The 3-a'mino-1,2,8,9-tetraazaphenalenes obtained from the intermediates of the present invention are cardiovascular agents, in particular, blood pressure lowering agents and are used in counteracting hypertension. They also manifest coronary and peripheral vascular dilation properties, effects on the central nervous system and antiinflammatory activity. They can be administered parenterally or orally in any of the usual pharmaceutical forms including tablets, capsules, powders, suspensions, solutions, syrups and the like, including sustained release preparations which can be compounded by any of the known procedures.

These 3-amino-l,2,8,9-tetraazaphenalenes are prepared through treatment of a 3-chloroor 3-bromo-1,2,8,9-tetraazaphenalene of the present invention with the appropriate amine.

In the above R R and R are as previously defined and each of R and R taken separately is hydrogen, (lower)alkyl, phenyl, benzyl, or chlorophenyl or R and R and the nitrogen atom to which they are attached when all are taken together, are pyrrolidino, piperidino, hexamethyleneimino, piperazino, N'-alkylpiperazino, morpholino, 2-al-kylmorpholino, 2,6-dialkylmorpholino, 1,2,3,4- tetrahydroisoquinolino, 1,2,5,6-tetrahydropyridino or the like cyclic amines.

The reaction is executed by simply heating a mixture of the reactants optionally in an inert organic solvent such as methylcellosolve, diglyme, triglyme or the like. Generally excess amine is employed, and in the case of lower boiling amines, increased pressure may be utilized.

The 3-chloro and 3-bromo-l,2,8,9-tetraazaphenalenes of the present invention can be prepared by several routes.

In one method a 3-keto-2,3-dihydro-l,2,8,9-tetraazaphenalene is treated with an excess phosphorus oxychloride or phosphorus pentachloride and phosphorus oxychloride or phosphorus oxybromide or phosphorus pentabromide and phosphorus oxybromide at elevated temperatures, e.g. at reflux, until a chloro or bromo group is introduced in the 3-position. This transformation may be represented as follows:

N "T \N t NRl 1 R3 R3 N N in la III I Alternatively, the 3-chloro and 3-bromo-l,2,8,9-tetraazaphenalene compounds of Formula I can be prepared from the corresponding 3-unsubstituted l,2,8,9-tetraaza phenalenes through the action of chlorine or bromine in the presence of sodium acetate.

The above mentioned 3-keto-2,3-dihydro-l,2,8,9-tetraazaphenalenes and 3 unsubstituted-l,2,8,9-tetraazaphenalenes are the subject of copending applications filed herewith. Briefly one preparation of such compounds involves the following:

VII

With greater particularity to the above reaction scheme, the starting material is a compound of Formula IV wherein R is as previously defined, A is dibromomethyl, an aldehyde group, or benzoyl and each of B and B is a carboxyl group or a group the oxidative state of which corresponds to that of a carboxyl group, including acid halides, anhydrides, esters and lactones thereof. Representative compounds of Formula IV thus include 3-dibromomethylphthalic anhydride, 3 hydroxy-7-carboxyphthalide, 2-dibromomethyl-G-carbethoxybenzoic acid. A compound of Formula IV is then treated with a single molar equivalent of a hydrazine to yield the substituted 1(2H)phthalazinone of Formula V wherein R is hydroxy. This, or the corresponding derivative wherein R is alkoxy, chloro or bromo, when treated with hydrazine, yields the 3-keto-2,3-dihydro-1,2,8,9-tetraazaphenalene of Formula III which is converted directly to the 3-chloroor 3-bromo-1,2,8,9-tetraazaphenalene of Formula I as previously described. Alternatively the keto compound of Formula III is treated with phosphorus pentasulfide in, for example, refluxing pyridine to yield the corresponding 3 thiono-2,3-dihydro-1,2,8,9-tetraazaphenalene of Formula VI. This thiono compound is then treated with Raney nickel in an inert organic solvent such as methyl cellosolve to yield the corresponding 3-substituted 1,2,55,9- tetraazapheualenes of Formula VII.

Included within the scope of the present invention are the acid addition salts of these novel tetraazaphenalene derivatives, obtained via the conventional methods. Typical salts thus include those derived from hydrochloric, hydrobromic, sulfuric, phosphoric, methanesulfonic, acetic, lactic, succinic, embonic, malic, maleic, aconitic, phthalic, tartaric and the like acids. Quaternary salts derived from alkyl halides are also within the scope of this invention.

The following examples, presented for illustration and not limitation, will serve to further typify the nature of v the present invention. In these examples temperature is expressed in degrees centigrade.

EXAMPLE 1 3-chloro-9-phenyl-1,2,8,9-tetraazaphenalene (a) 3-dibromomethylphthalic anhydride: A mixture of B-methylphthalic anhydride (81 g.), N-bromosuccinimide (182 g.), benzoyl peroxide (40 mg.) and carbon tetrachloride (1500 ml.) is irradiated and heated to reflux by a 100 watt insertion-type ultraviolet lamp under stirring and exclusion of moisture. After the mixture becomes brick red, an additional 40 mg. of benzoyl peroxide is added. Illumination at reflux is carried out during 24 hours. The mixture is cooled and filtered free of succinimide and the filtrate is evaporated in vacuo. The residual yellowish brown solid is dissolved in hot ether, treated with decolorizing charcoal and filtered. Addition of hexane to the filtrate affords the crystalline product, M.P. 90.5-93 C. in 72% yield. Two recrystallizations from ether-lhexane yield colorless needles melting at 93-95 C.

Calcd. for C H Br O (percent): C, 33.78; H, 1.26; Br, 49.92. Found (percent): C, 33.66; H, 1.20; Br, 49.41.

(b) 3-hydroxy-7-carboxyphthalide: 3-dibromomethylphthalic anhydride (40 g.) is added in small portions to a hot solution of 2 N sodium hydroxide (500 ml.) with stirring. After ten minutes, the clear solution is rendered strongly acidic with concentrated hydrochloric acid and heated for one-half hour at The solution is evaporated to dryness in vacuo and the residue is dissolved in hot water (600 ml.), treated with decoloriing charcoal and filtered.

After three days at 5 C., the colorless filtrate yields 21.3 g. (88%) of colorless blocks, M.P. 1635-166 C. The analytical sample, M.P. 1655-1685 C., is obtained after two further crystallizations from water.

Calcd. for C H O (percent): C, 55.68; H, 3.12. Found (percent): C, 55.98; H, 2.99.

(c) 8-carboxy-2-phenyl-1(2H)-phthalazinone: A mixture of phenylhydrazine (3.6 ml.), 3-hydroxy-7-carboxyphthalide (5.82 g.) and glacial acetic acid ml.) is heated under reflux for 18 hours. The clear solution is evaporated to dryness in vacuo and the residual solid triturated with methanol and collected. The product (6.97 g.), M.P. 197-199, is recrystallized from benzene and a colroless crystalline product, M.P. 197198 obtained.

Calcd. for C H N O (percent): C, 67.66; H, 3.79; N, 10.52. Found (percent): C, 67.28; H, 3.75; N, 10.82.

The infrared spectrum (Nujol) shows prominent peaks at 1720 cm.- (carboxyl group) and 1650 cmr (amide carbonyl).

(d) 8-carbethoxy-2-phenyl-1(2H)phthalazinone: To a solution of thionyl chloride (40 ml.) in chlorobenzen (150 ml.) is added under stirring 8-carboxy-2-phenyl- 1(2H)phthalazinone (24.3 g.) and the mixture heated at reflux with exclusion of moisture for 2 hours. When the evolution of gas has ceased, the solution is evaporated to dryness in vacuo. The residual white solid (24.7 g.) is treated with absolute ethanol (350 ml.) and heated under reflux for 18 hours. The solution is filtered hot and allowed to cool slowly. The ester precipitates in colorless needles, M.P. 150-151". The melting point is unchanged after recrystallization from ethanol.

Calcd. for C H N O (percent): C, 69.37; H, 4.79; N, 9.52. Found (percent): C, 69.08; H, 4.65; N, 9.36.

(e) 3 keto-9-phenyl 2,3-dihydro 1,2,8,9 tetraazaphenalene: A mixture of 2-phenyl-8-carbethoxy-1(2H) phthalazinone (11.76 g.), 100% hydrazine hydrate (40 ml.) and methyl cellosolve (160 ml.) is heated at reflux for 25 hours. The yellow solution is filtered and treated with methanol (100 ml.) followed by water dropwise under stirring. A flocculent yellow precipitate forms. The mixture is cooled and the product collected, washed thoroughly with water and ethanol and dried in vacuo. The solid (4.44 g.) M.P. 254-6, is recrystallized from methyl cellosolve and obtained as yellow needles, M.P. 255-7.

Calcd. for C H N O (percent): C, 68.70; H, 3.85; N, 21.37. Found (percent): C, 68.81; H, 3.90; N, 21.20.

(f) 3-chloro-9-phenyl-1,2,8,9-tetraazaphenalene: To a stirred mixture of phosphorus pentachloride (6.3 g.) in phosphorus oxychloride (40 m1.) is added finely powdered 3-keto-9-phenyl-2,3-dihydro 1,2,8,9 tetraazaphenalene (7.8 g.). The mixture is stirred at reflux for 165 minutes under moisture exclusion and then poured cautiously into ice. The mxiture is made alkaline under cooling with sodium hydroxide solution and the fine yellow precipitate which forms is collected and washed with water. As this material still contains inorganic solid, It is stirred for /2 hour in 600 ml. of warm (50) water and again filtered. The precipitate is recrystallized from ethanol and 5.4 g. of yellow crystals, M.P. 225-228,

obtained.

EXAMPLE 2 3-chloro-9-methyl-1,2,8,9-tetraazaphenalene (a) 3-keto-2,3-dihydro 1,2,8,9 tetraazaphenalene: A suspension of a,a dibromo-3-methylphthalic anhydride (80 g.) in ethanol (500 cc.) is treated with a solution of 100% hydrazine hydrate (100 cc.) and water (100 cc.) dropwise under stirring and cooling. A white suspension forms. After the addition, the temperature is raised gradually to reflux, whereupon the white suspension disappears and a yellow precipitate forms. After 88 hours at reflux, the mixture is cooled, filtered and the first crop of product is washed with water and ethanol and dried in vacuo, dissolved in 500 ml. of glacial acetic acid and heated under reflux for 18 hours. The mixture is cooled and filtered and a second crop of the product obtained. The overall yield of product, M.P. 347, is 25.7 g., or 55% of theory. The product is recrystallized from 3 liters of boiling dimethylformamide and obtained as a yellow powder which, on heating, forms a microcrystalline solid at 220270 C. and melts above 350 C.

Calcd. (percent): C, 58.06; H, 3.25; N, 30.09. Found (percent): C, 57.92; H, 3.58; N, 30.28; C, 58.03; H, 3.52.

(b) 3-keto 9 methyl 2,3 dihydro-1,2,8,9-tetraazaphenalene: To a stirred suspension of sodium methoxide (0.7 g.) in dry dimethylsulfoxide (100 ml.) is added 3- keto-2,3-dihydro-1,2,8,9-tetraazaphenalene (1.86 g.). This is stirred at 60 under moisture exclusion until a red solution has formed. This is cooled to 50 C. and methyliodide (1 ml.) is added. The solution darkens, and after 20 minutes, more methyliodide (1 ml.) is added and the solution is poured into ice water (500 ml.) containing 0.5 g. of sodium bisulfite and 4 ml. of glacial acetic acid. The mixture is cooled overnight and then filtered. The product is collected by filtration, washed with water and dried. The yellow solid (1.2 g.) is twice recrystallized from methyl cellosolve and clarified with charcoal, to yield the product, M.P. 289-293".

(c) 3-chloro-9-methyl-l,2,8,9-tetraazaphenalene: To a stirred mixture of phosphorus pentachloride (11.25 g.) in

phosphorus oxychloride ml.) is added 3-keto-9-methyl-2,3-dihydro-l,2,8,9-tetraazaphenalene. This mixture is stirred at reflux under moisture exclusive for 2 hours and then poured into ice and rendered basic under stirring and cooling with 20% sodium hydroxide solution. The yellow solid is collected, washed thoroughly with water and dried in a dessicator over phosphorus pentoxide. The product (8.63 g.) is recrystallized twice from ethanol with clarification over charcoal to yield 4.75 g. of product, M.P. 253255 (dec.).

In a similar fashion to that described in part (c) of this example, 3-keto-2,3-dihydro-1,2,8,9-tetraazaphenalene is converted to 3-chloro-1,2,8,9-tetraazaphenalene which as the methanesulfonate salt melts at 246-249 (dec.).

EXAMPLE 3 3-chloro-7-phenyl-1,2,8,9 tetraazaphenalene (a) 8-carboxy-4-phenyl-1(2H)phthalazinone: A mixture of 32.5 g. of 3-benzoylphthalic acid and 85 ml. of hydrazine hydrate in 145 ml. of water is heated at reflux for 18 hours. Upon cooling and acidification with hydrochloric acid, the product forms as a solid. This is collected and recrystallized from glacial acetic acid, M.P. 257-259".

(b) 8-carbomethoxy 4 phenyl-l(2H)phthalazinone: The product of part (a) (19.0 g.), 32 ml. of thionyl chloride and 115 ml. of chlorobeuzene is heated at reflux with stirring and exlusion of moisture for 3 hours. The solid obtained upon concentration under reduced pressure is taken up in 300 "ml. of methanol and this solution is then heated at reflux for 18 hours. Upon cooling the product, M.P. 198-202", is collected and can be used directly in the next step.

(c) 3 keto-7-phenyl-2,3-dihydro-1,2,8,9-tetraazaphenalene: A mixture of 18.6 g. of 8-carbomethoxy-4-phenyl- 1(2H)phthalazinone, 400 ml. of hydrazine hydrate and ml. of water is heated at reflux for 20 hours. The solid which forms upon cooling is collected, washed with water and recrystallized from methyl cellosolve, M.P. over 350 C.

(d) 3-chloro 7 phenyl-1,2,8,9-tetraazaphenalene: A mixture of 3-keto-7-phenyl-2,3-dihydro 1,2,8,9 tetraazaphenalene (5 g.), phosphoryl chloride (27 ml.) and phosphorus pentachloride (4 g.) is heated at reflux under moisture exclusion. The mixture is then concentrated under reduced pressure, taken up in acetone and quenched in ice-water. The solid product is collected, washed with cold water and dried, M.P. 278-288 C.

EXAMPLE 4 3-chloro-9-benzy1-1,2,8,9-tetraazaphenalene A mixture of 3-keto-9-benzyl-2,3-dihydr0-1,2,8,9-tetraazaphenalene (47 g.), phosphorus oxychloride (340 ml.) and phosphorus pentachloride (43 g.) is heated at reflux with exclusion of moisture for 1% hours. The reaction mixture is then evaporated to dryness at reduced pressure and the residue taken up in acetone. This acetone solution is poured into ice water with stirring and the resultant mixture is rendered basic with 20% sodium hydroxide solution and extracted with chloroform. The chloroform extracts are washed with water, dried over sodium sulfate and concentrated to dryness at reduced pressure to yield the product which is purified through recrystallization from a mixture of methyl cellosolve and ethanol, M.P. 203.5207.5

Further purification may be effected through passage of a chloroform solution of the product over neutral alumina followed by recrystallization from benzene, M.P. 208-209".

EXAMPLE 3-bromo-9-methyl-l,2,8,9-tetraazaphenalene (a) 9-methyl-1,2,8,9-tetraazaphenalene: 3-keto-9-rnethyl-2,3-dihydro-1,2,8,9-tetraazaphenalene (9.0 g.) in 120 ml. of dry pyridine and 12 g. phosphorus pentasulfide are mixed with stirring and refluxed for 2.5 hours. The mixture is poured into an ice-salt mixture, stirred for 30 minutes and filtered. The solid thus collected is dried and recrystallized from methyl cellosolve to yield 3-thiono-9- methyl-2,3-dihydro-l,2,8,9-tetraazaphenalene, M.P. 299- 316 C.

3 thiono 9-methyl-2,3-dihydro-l,2,8,9-tetraazaphenalene (1.08 g.) is suspended in ethanol (200 ml.) and treated with Raney nickel (about 5 g.) in ethanol added in several portions. After the addition is complete, the mixture is stirred for one hour on the steam bath and then filtered hot. The filtrate is evaporated in vacuo, taken up in ethanol and again filtered. Evaporation of the ethanol solution yields a yellow solid (0.60 g.). The product is purified by one recrystallization from benzenehexane. Yellow crystals (0.40 g.) are obtained melting in the range 145447".

Calcd. for C H N (percent): C, 65.20; H, 4.38; N, 30.42. Found (percent): C, 65.03; H, 4.59; N, 30.15.

(b) 3-bromo-9-methyl-1,2,8,9-tetraazaphenalene: To a solution of 9-methyl-1,2,8,9-tetraazaphenalene (368 mg.) and 165 mg. of anhydrous sodium acetate in ml. of

glacial acetic acid are added in a dropwise fashion with stirring 320 mg. of bromine in 25 ml. of glacial acetic acid. The mixture is stirred for 18 hours and then poured into water, filtered and concentrated to dryness. The solid is triturated with warm water, filtered and recrystallized from ethanol to yield the product, M.P. 237-238".

Calcd. for C H- N Br (percent): C, 45.65; H, 2.68; N, 21.29. Found (percent): C, 45.30; H, 2.57; N, 21.54.

8 What is claimed is: 1. A compound of the formula:

wherein R is hydrogen, (lower)alkyl, phenyl or phenyl(lower) alkyl;

R is hydrogen or phenyl;

R is hydrogen, chloro, bromo, hydroxy, (l0wer)-alkoxy,

carboxy or nitro; and

Y is chloro or bromo.

References Cited UNITED STATES PATENTS l/1969 Doebel et al. 260250 2/l969 Doebel et al 260250 NICHOLAS S. RIZZO, Primary Examiner US. Cl. X.R. 424250 

